In order to increase an integration level of arrays, a NAND flash memory device may include a predetermined number of NAND type memory cells. The number of contacts provided in a cell array of a NAND flash memory device is less than the number of contacts in a cell array of a NOR flash memory device. Thus, the NAND flash memory device may have a relatively small chip size. Therefore, according to the trend toward high integration and large capacity of a semiconductor memory device, the demand for NAND flash memory devices is on the rise.
The cell arrays provided in a NAND flash memory device are formed in a single layer on a semiconductor substrate. However, to cope with the trend toward high integration and large capacity of a semiconductor memory device, the sizes of cell arrays to be implemented on a plane of the single layer may be reduced while the number of cell arrays is gradually increased. According to the development of a highly integrated, large capacity NAND flash memory device, the NAND flash memory device may have vertical type cell arrays.